The periodical cicada in WVa. . rs tocorrespond to a tongue. IS, tongue from side. A SEVENTEEN YEAR AND A THIRTEEN YEAR RACE. In the southern or warmer sections of the U. S., the broodsor swarms of the insect appear at regular periods of thirteenyears, while in northern or colder sections, they appear everyseventeen years. Thus the broods of the former are referredto as belonging to a thirteen year race; while those of the lat:ter belong to a seventeen year race. TWO DISTINCT FORMS OF THE ADULT. Two distinct forms or varieties of the insect occur in all 10 WEST VIRGINIA EXPERIMENT STATION. bro
The periodical cicada in WVa. . rs tocorrespond to a tongue. IS, tongue from side. A SEVENTEEN YEAR AND A THIRTEEN YEAR RACE. In the southern or warmer sections of the U. S., the broodsor swarms of the insect appear at regular periods of thirteenyears, while in northern or colder sections, they appear everyseventeen years. Thus the broods of the former are referredto as belonging to a thirteen year race; while those of the lat:ter belong to a seventeen year race. TWO DISTINCT FORMS OF THE ADULT. Two distinct forms or varieties of the insect occur in all 10 WEST VIRGINIA EXPERIMENT STATION. broods or swarms of both the thirteen year and seventeen yearraces, which are easily distinguished by the difference in size,and in the sound produced by the males. The Larger variety(Plate 1, e and f) which is the typical form of the species is al-ways more abundant and produces the familiar f-a-r-r-o sound,while the other (Plate L, g) is much smaller and its note ismore shrill and quite different from that of its larger Front legs of periodical cicada; 19, front legs of pupa; 20, front leg ofadult female, enlarged 3£ times. DISTRIBUTION AND NUMBER OF BROODS. The species appears to be confined in its natural distributionto the United States and to occur in all of the States east ofthe Rocky Mountains, except Maine, JNew Hampshire and Ver-mont. Within the area occupied by it there is, according toDr. C. V. Riley, over twenty distinct broods, of which seven oreight belong to the 13 year race and thirteen or fourteen to the17 year race. It has also been determined that there is such adiversity in the areas occupied by each brood and the years inwhich swarms of the different broods occur, that the insect ap-pears somewhere in the United States nearly every year. THE DIFFERENT BROODS DESIGNATED BY ROMAN NUMBERS. In 1868, the late Dr. C. V. Riley, then State entomologist ofMissouri, designated all of the broods known* or supposed to THE PERIODICAL CICADA. 1 1 occur in the Un
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Keywords: ., bookauthorhopkinsadandrewdelmar, bookcentury1800, bookdecade1890
